Single beamlet optics studies and functional optimization of the MITICA accelerator

The ITER Neutral Beam Test Facility (PRIMA) is plan ned to be built at Consorzio RFX (Padova, Italy). PRIMA includes two experimental devices: an ITER-si ze ion source with low voltage extraction called SPIDER and the prototype of the ITER Heating Neutra l Beam Injector (HNB) called MITICA. The purpose of MITICA is to demonstrate that all th e operational parameters of the ITER HNB accelerato r can be experimentally achieved with reasonable marg in, thus establishing a large step forward in the performances of neutral beam injectors in compariso n with the present experimental devices. The design of the MITICA accelerator, here describe d in detail, has been developed in order to satisfy with reasonable margin all the operational requirements of the ITER HNB. An integrated approach, taking int o consideration at the same time physics and engineer ing aspects, has been adopted throughout the design process. Particular care has been applied also to s upporting and validating the design on the basis of the expertise and experimental data made available by t he neutral beam laboratories of CEA, IPP, CCFE, NIF S and JAEA. The aim of this report is to finalize the design of the MITICA accelerator, by comparing the design co ncepts that were found to be the best performing from prev ious analyses and choose the most suitable one to b e adopted in the MITICA experiment. An optimization p rocess is set up by developing subsequent design solutions through discussion and comparisons of the results of simulations, taking into account the advantages and drawbacks of the different design ch oices. This report presents a the studies on differ ent possible geometries and magnetic configurations for the MITICA accelerator carried out during 2014.